Application Notes

Typical Configurations for GLR1000, GLR2000, and GLR3000 Series Bridge/Router

Introduction

GL’s Linux based routers, along with PacketProbe, can monitor VOIP traffic through a number of configurations. Performance will depend on the type of router used, based on their CPU and memory characteristics. The basic unit is the GLR2000 which is intended for monitoring low numbers of calls, followed by the GLR3000.

Following are examples of configuration with the PacketProbe software application acting as an interface to a PacketScanWeb database. It can also be terminated with a simple client application.

1. Basic Router
   In a basic configuration, the Ethernet ports of the bridge/router can be configured with sub-nets and packets will be routed across automatically based on the IP address.
   
   
   
   
2. Bridge Probe
   A variation of the routing is to set up the Ethernet ports as a Bridged Virtual Interface. All packets seen on one port will be automatically routed to the other port.
   
   
   
   
3. WAN Interface PPP
   Interface cards installed in the router are configured as a LAN-to-WAN interface. For example, a DS3/E3 card is installed and configured to support a PPP (Point-to-Point Protocol) link. PPP is a data link protocol commonly used to establish a direct connection between two networking nodes. The routers configuration table includes the route to the far side network as well as the DS3/ E3 interface settings, framing, clock recovery, etc. This is a common configuration for connecting a remote office to a network.
   
   In a PPP configuration, as shown in the figure below, the DS3 is non-channelized. Once the PPP connection is established, the Link Control Protocol provides automatic configuration of the interfaces at both ends. The effective throughput on PPP connections is increased by compressing the amount of data in the frame packets across the link. The protocol decompresses the frame at its destination.
   
   
   
   
4. WAN Interface MLPPP
   Another example is to install a T1/E1 card that for multiple trunk versions can be configured for separate PPP links to different destinations or the multiple links could be aggregated into a Multi-link PPP connection or MLPPP. Multilink PPP is a method for spreading traffic across multiple distinct PPP connections. This configuration is used to provide load balancing over the router interfaces that PPP uses.
   
   Multiple E1/T1 interface cards are installed and the routers configuration table includes the route to the far side network as well as the T1/E1 interface settings, framing, clock recovery, etc. There are Dual and Quad versions of the interface card.
   
   
   
   
5. Synch Serial
   VSAT Internet equipment has IP routers built inside modems that provide Ethernet connection for local networks. Point-to-Point satellite connectivity services based on traditional SCPC technology require an external IP router with a serial card to interface V.35, EIA-232, G.703 or Serial LVDS to connect to the SCPC satellite modem.
   
   The V.35 synchronous interface is generally the standard for VSAT and other satellite modems though there are variations for individual satellite system suppliers. This configuration provides a low cost solution for interfacing to teleport-based equipment.
   
   Some businesses and even countries use VSAT technology to provide remote access and to replace old VHF radio transmission links. Conventional end point indoor units include a 2-W and data port. With VoIP even the 2-W connection could be eliminated.
   
   

Pricing
Price will vary based on the WAN card (serial interface) installed, if required, desired interface and configuration, T1/E1, DS3, PPP, ML-PPP etc. The hardware can be configured using a simple configuration file. Please click GLR1000, GLR2000 or GLR3000 to obtain price information.